This invention relates generally to a quality improvement process for alpha-olefins and more specifically to a process for the removal of dienes from alpha-olefins, without substantial isomerization of the alpha-olefins to internal olefins, achieved by contacting the alpha-olefins with acid treated montmorillonite clays.
The preparation of linear, C.sub.4 to C.sub.30 alpha-olefin mixtures by ethylene chain growth using triethylaluminum followed by ethylene displacement is a well known process. The olefin type produced is mainly alpha-olefins, i.e., R--CH.dbd.CH.sub.2, where R is an aliphatic hydrocarbon group but the product also contains small amounts of internal olefins, R--CH.dbd.CHR, where R is an aliphatic hydrocarbon group, vinylidene olefins R.sub.2 C.dbd.CH.sub.2 where each R is an aliphatic hydrocarbon group and dienes which may be straight or branched chain conjugated dienes. The products can be separated into single or mixed carbon number olefins by distillation for selected end uses. Lower carbon number olefins such as hexene-1 and octene-1 are useful, for example, as comonomers in olefin polymerizations and the presence of impurities such as vinylidene olefins and conjugated dienes may interfere in such uses. It is therefore desirable to remove or reduce the amounts of these impurities. At the same time, the removal process should not substantially affect the alpha-olefin such as by converting it to other olefin species. We are aware that an acid clay treatment bed of some type has been used by others to remove cyclopentadiene, formed in connection with a catalytic polymerization process, from a recycle diluent stream.